Reactor staging influences microbial community composition and diversity of denitrifying MBBRs- Implications on pharmaceutical removal

WATER RESEARCH

卷:138

Article

Torresi, Elena^1,2  Gulay, Arda¹  Polesel, Fabio¹  Jensen, Marlene M.¹  Christensson, Magnus²  Smets, Barth F.¹  Plosz, Benedek Gy.^1,3 

[1] Tech Univ Denmark, DTU Environm, Bygningstorvet B115, DK-2800 Lyngby, Denmark

[2] Veolia Water Technol AB, AnoxKoldnes, Klosterangsvagen 11A, SE-22647 Lund, Sweden

[3] Univ Bath, Dept Chem Engn, Bath BA2 7AY, Avon, England

关键词: Moving bed biofilm reactors;    Micropollutant removal;    Organic carbon;    Structure-function relationships;    Heterotrophic denitrification;   

DOI  :  10.1016/j.watres.2018.03.014

来源: Elsevier

【 摘 要 】

The subdivision of biofilm reactor in two or more stages (i.e., reactor staging) represents an option for process optimisation of biological treatment. In our previous work, we showed that the gradient of influent organic substrate availability (induced by the staging) can influence the microbial activity (i.e., denitrification and pharmaceutical biotransformation kinetics) of a denitrifying three-stage Moving Bed Biofilm Reactor (MBBR) system. However, it is unclear whether staging and thus the long-term exposure to varying organic carbon type and loading influences the microbial community structure and diversity. In this study, we investigated biofilm structure and diversity in the three-stage MBBR system (S) compared to a single-stage configuration (U) and their relationship with microbial functions. Results from 16S rRNA amplicon libraries revealed a significantly higher microbial richness in the staged MBBR (at 99% sequence similarity) compared to single-stage MBBR. A more even and diverse microbial community was selected in the last stage of S (S3), likely due to exposure to carbon limitation during continuous-flow operation. A core of OTUs was shared in both systems, consisting of Burkholderiales, Xanthomonadales, Flavobacteriales and Sphingobacteriales, while MBBR staging selected for specific taxa (i.e., Candidate division WS6 and Deinococcales). Results from quantitative PCR (qPCR) showed that S3 exhibited the lowest abundance of 16S rRNA but the highest abundance of atypical nosZ, suggesting a selection of microbes with more diverse N-metabolism (i.e., incomplete denitrifiers) in the stage exposed to the lowest carbon availability. A positive correlation (p<0.05) was observed between removal rate constants of several pharmaceuticals with abundance of relevant denitrifying genes, but not with biodiversity. Despite the previously suggested positive relationship between microbial diversity and functionality in macrobial and microbial ecosystems, this was not observed in the current study, indicating a need to further investigate structure-function relationships for denitrifying systems. (C) 2018 Published by Elsevier Ltd.

【 授权许可】

Free